Enum DatumCow

pub enum DatumCow<'a> {
    Borrowed(DatumRef<'a>),
    Owned(Datum),
}

🐮 A borrowed DatumRef or an owned Datum.

We do not use std::borrow::Cow because it requires the borrowed variant to be a reference, whereas what we have is a DatumRef with a lifetime.

Usage

Generally, you don’t need to match on the variants of DatumCow to access the underlying datum. Instead, you can…

• call to_datum_ref to get a borrowed DatumRef without any allocation, which can be used to append to an array builder or to encode into the storage representation,

• call to_owned_datum to get an owned Datum with potentially an allocation, which can be used to store in a struct without lifetime constraints.

Variants

Borrowed(DatumRef<'a>)

Owned(Datum)

Implementations

impl DatumCow<'_>

pub const NULL: DatumCow<'static> = _

Equivalent to DatumCow::Owned(Datum::None).

Trait Implementations

impl<'a> Clone for DatumCow<'a>

fn clone(&self) -> DatumCow<'a>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Debug for DatumCow<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Option<ScalarImpl>> for DatumCow<'_>

fn from(datum: Datum) -> Self

Converts to this type from the input type.

impl<'a> From<Option<ScalarRefImpl<'a>>> for DatumCow<'a>

fn from(datum: DatumRef<'a>) -> Self

Converts to this type from the input type.

impl PartialEq for DatumCow<'_>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ToDatumRef for DatumCow<'_>

fn to_datum_ref(&self) -> DatumRef<'_>

Convert the datum to DatumRef.

impl ToOwnedDatum for DatumCow<'_>

fn to_owned_datum(self) -> Datum

Convert the datum to an owned Datum.

impl Eq for DatumCow<'_>